1. Field of the Invention
The present invention relates to a vehicle seat, and more particularly to a vehicle seat with a height adjustable seat cushion.
2. Description of the Prior Art
In Japanese Patent Laid-open Publication No. 52(1977)-71020, there has been proposed a vehicle seat, the seat cushion of which is composed of a cushion body mounted on a cushion frame and a movable cushion assembled within the cushion body and supported by a lift mechanism to be raised to an upper position for child use or moved down to a lower position where the seating surface of the movable cushion is placed at the same height as that of the cushion body for adult use.
Since in the vehicle seat, the movable cushion is completely separated from the cushion body when lifted to the upper position, an infant or child seated on the movable cushion may not be maintained in a stable manner as both of his legs are afloat in the air. It is, therefore, desirable that the infant or child can be supported at his legs in a stable manner.
In European Patent No. 0666194, there has been proposed a vehicle seat, the seat cushion of which is divided-into three cushions in a fore-and-aft direction. The front cushion of the vehicle seat is rotatably mounted on a front end of a cushion frame at its front-side lower end to be tilted forward or backward, and the intermediate cushion is rotatably connected at its rear-side lower end to a front-side lower end of the rear cushion supported by a lift mechanism. In the vehicle seat, the rear cushion is raised by the lift mechanism to provide a seat cushion for child use, and the front cushion is tilted forward to provide a foot rest for a child seated on the rear cushion. Thus, the child seated on the rear cushion can be supported in a stable manner as both of his legs and femurs are placed on the front and intermediate cushions.
In the vehicle seat, however, the rear cushion is shortened in the fore-and-aft direction since the seat cushion is divided into three portions. As a result, the rear cushion may not be a comfortable seat for child use. In addition, if the thickness of the seat cushion is increased to provide a comfortable seat for child use, a front-side upper edge of the rear cushion would be spaced a large distance from a tear-side upper edge of the intermediate cushion. This causes a sense of incongruity for a user. On the contrary, if the thickness of the seat cushion is reduced to eliminate such a space between the intermediate and rear cushions, the seating comfort of the rear cushion is deteriorated.